class_docstr: Pan-zoom transform
  
  Parameters
  ----------
  canvas : instance of Canvas | None
      The canvas to attch to.
  aspect : float | None
      The aspect ratio to apply.
  **kwargs : dict
      Keyword arguments to pass to the underlying `STTransform`.
code: def __init__(self, canvas=None, aspect=None, **kwargs):
      self._aspect = aspect
      self.attach(canvas)
      STTransform.__init__(self, **kwargs)
      self.on_resize(None)
  
file_path: vispy/vispy/visuals/transforms/interactive.py
imports: from __future__ import division
  import numpy
  from .linear import STTransform
label_desc: Use image node_id 1 to create a new PanZoomTransform object from inherited base classes: STTransform with example: obj = PanZoomTransform(canvas, aspect)